Heat-exchange installations comprise heat exchangers which are generally of two types.
The first type of heat exchanger comprises a bundle of U-shaped tubes or a bundle of straight tubes through which one of the fluids circulates.
However, this type of exchanger is of expensive design and the thermal efficiency is limited, given that the number of tubes depends on the space available which, in most instances, is restricted.
The second type of heat exchanger comprises a sealed vessel in which there is installed a bundle of plates arranged contiguously and parallel to each other.
The plates, which consist of thin sheets, usually made of stainless steel, have smooth-surfaced edges and a corrugated central region via which they are in contact with one another and via which they delimit channels that form circuits for the circulation of independent fluids.
This type of heat exchanger with bundles of plates operates with various fluids such as, for example, liquids or gases or two-phase mixtures.
With this plate-type exchanger, with the two liquids circulating through the respective circuits, there is heat exchange between these two fluids, and this heat exchange allows one of the fluids to be heated up and the other cooled, or vice versa.
For certain industrial applications, it is necessary to obtain a substantial temperature difference of the fluid to be heated or cooled between its entry into and exit from the plate-type exchanger.
This is why, in such an instance, several plate-type exchangers are arranged in sequence.
Each plate-type heat exchanger is made up of a sealed vessel in which there is arranged a plate bundle delimiting two circuits, one of which is intended for the main fluid that is to be heated or cooled.
These main circuits of the various plate bundles are interconnected by connecting pipes which pass through each vessel in a sealed way so as to allow the main fluid to circulate continuously through the various plate bundles.
As a result, the floor space required for this kind of installation is great and the cost of manufacturing and maintaining it is also high.
Furthermore, the connecting pipes between the various exchangers for transferring the main fluid between these exchangers constitute regions where there are needless and parasitic pressure drops and regions where heat is lost, and this reduces the efficiency of the heat-exchange installation.